Anne Hathaway has poked fun at those who suggested her baby bump didn’t look real after a recent film premiere, telling them she had “fake hair, real bump”.

The US actress turned heads in an outfit that showed off her bare bump at the launch of her new film, The End of Oak Street, in Los Angeles on Sunday.

It sparked a flurry of comments on social media from people saying “Why does it look fake?” and “Oh come on. That is not real.”

But others came to her defence, with one writing: “A lot of people in these comments have never seen a pregnant belly on someone who has abs.” Another questioned: “Can women exist, damn,” while someone else posted: “People always commenting about women is insane.”

Hathaway, 43, announced in June that she is expecting her third child with husband Adam Shulman.

Celebrities are often judged on their choice of red carpet wear, but Hathaway’s outfit at the premiere for The End of Oak Street has attracted particular attention.

Her bump was partially exposed in the custom Atelier Prabal Gurung crop top, which the designer described as a “sculptural high-low halter top with a cascading train”. Hathaway paired the top with low-rise La Ligne jeans and red Aquazzura stilettos.

“Fake hair, real bump,” the actress wrote on Instagram with a video of her getting ready and attending the premiere.

“Enjoy The @endofoakstreet Block Party chaos with me as my outfit literally melts in the heat!!”

As well as raising unfounded doubts about the bump, some people criticised the star’s attire on social media, calling it “ridiculous”, “tacky” and “bizarre”.

But others praised her. Charlotte Cripps wrote in the Independent: “It might be an outfit that her social media critics wouldn’t be seen dead in, but it’s a clear message of body positivity, strength, and gender equality – and it’s her unique expression of the next chapter of her life.”

An op ed in Vogue stated: “What the rest of us need to realise is that a woman’s baby bump is none of our business (can’t believe this still needs saying).

“What if, instead, we celebrated the fact that a woman’s body is doing something amazing, rather than telling her that she looks shameful, fake, “over the top” or “awful and a bit weird”? Now that really would be radical.”

The Telegraph’s Rebecca Cope said: “Though drawing criticism from some, the look is just the latest example of a celebrity literally letting it all hang out.”

Hathaway’s appearance on Sunday also led to a surge in interest in her “coconut water” nails look.

The star has been in the spotlight throughout the summer, promoting The Odyssey at its premiere in London on 6 July (below).

She also donned red carpet maternity wear at The Odyssey’s US premiere in New York on 14 July.